1. Field of the Invention
The present invention relates to a coordinate detecting device for detecting the coordinate position, designated with a pen or a finger, and a method therefor.
2. Related Background Art
For entering the coordinate there are already known devices of various types, such as (1) resistive film (pressure sensing) system, (2) electrostatic capacitance coupling, electromagnetic induction and electromagnetic exchange systems, (3) ultrasonic system, (4) stilus pen system and (5) photointerruptor touch panel system.
The coordinate input device of the system (1) is constructed with two superposed sheets of glass or resinous film provided thereon with a resistive film (hereinafter collectively called "conductive film"), wherein two resistive films come into mutual contact to transmit a current at a designated position. The potential at the contacting position is detected to determine the resistance from a reference plane to the contacting point, whereby the position of contact is identified and converted into the positional coordinate.
The coordinate input device of the system (2) is composed of one, two or more glass plates or resinous sheets bearing linear or loop coil-shaped transparent electrode patterns aligned in the x and y directions of the input face, wherein a signal detected by an exclusive pen through an electromagnetic wave is processed to specify the transparent electrode pattern closest to the position designated by the pen. Thus the designated position is determined and converted into the coordinate value.
The device of the system (3) is provided with plural vibration detecting means (sensors) on a tablet constituting the input plane, to detect the vibration entered by vibration input means, wherein the distances from the vibration input means to the sensors are detected from the propagation speed of the vibration and the time required for propagation, and the coordinate of the input position is determined.
The device of the system (4) is to detect the CRT scanning signal with a stilus pen contacting the CRT, wherein the position on the raster pattern is specified from the detected timing of scanning and the coordinate value is determined.
In the device of the system (5), light beams such as of infrared light are provided as a network on the display face. When one of the beams is intercepted with a finger, a touch input is detected, and the coordinate of the input position is identified from the sensor detecting the interception of the light beam.
Also an information processing equipment in which the coordinate input device as explained above and a display device such as a liquid crystal display are integrally superposed allows to enter a gesture as a command with a pen-shaped tool on the display plane, to enter characters as a memorandum on the display, and to enter characters by character recognition.
Also in such information processing equipment, it is proposed to display a keyboard as a "virtual keyboard". In such case the coordinate input device utilizes the aforementioned system (1) based on the resistive films, since the input operations with fingers are required for use in place for the actual keyboard.
However such conventional coordinate input device, particularly that of the system (2), (3) or (4), requiring an exclusive pen for coordinate input, has been associated with a drawback that the input operation is not possible without such exclusive pen.
Also the device of the system (1), (3) or (4), only allows the coordinate input of a point at a time, do not allow entry of plural coordinates over a wide range at a time.
Also the information processing equipment utilizing the coordinate input device as explained above has been associated with the following drawbacks.
At first, a pen-shaped coordinate indicator is preferable for entering a gesture as a command, characters as a memorandum or a character for character recognition, but a conventional keyboard is faster and more convenient for entering text data (a large amount of character data). However, if the above-mentioned "virtual keyboard" is used instead of the ordinary keyboard, the entry of plural points is not possible on such "virtual keyboard" because the system (1) based on the resistive film has to be used.
As the input of plural points is not possible on the "virtual keyboard", it is not possible, unlike the ordinary keyboard, to use a key while [shift] key or [ctrl] key is depressed, but the input operation has to be made one at a time, such as depressing the [shift] key etc. at first and then depressing another key. Consequently the method of manipulation has to be modified from the ordinary operation. Besides the input operation is not possible in certain cases, such as the shortcut keys, so that such "virtual keyboard" cannot be a complete replacement for the conventional keyboard and cannot be used for high-speed input of a large amount of data.
In consideration of the foregoing, the object of the present invention is to provide a coordinate input device capable of simultaneous input of plural points.